Continuous casting mold



Filed June 11, 1965 United States Patent 3,339,588 CONTINUOUS CASTINGMOLD Paul Nilles, Embourg, Belgium, assignor to Centre National deRecherches Metallurgiques, Brussels, Belgium, a Belgian company FiledJune 11, 1965, Ser. No. 463,147 Claims priority, application gilrembourg, June 13, 1964,

46, 6 Claims. (Cl. 138145) The present invention relates to an ingotmold used for the continuous casting of metals and more particularly forthe continuous casting of steel.

In vertical continuous casting of metals, the molten metal is poured ina continuous fashion into a ingot mold which, usually, is made of copperand is open above and below. The metal solidifies superficially in thismold to form a pseudo-ingot that is to say an ingot which is notcompletely solidified, which is drawn out from below down through theingot mold.

The superficial solidification of the molten metal results from theintense cooling that it undergoes on making contact with the walls ofthe ingot mold which are cooled by the circulation of water.

In the course of the peripheral solidification of the metal it ishowever noted that the thin solidified skin tends to adhere or stick tothe walls of the ingot mold so as to cause tearing as the ingot is drawndownwards by the extraction mechanism placed below the mold.

Prior art workers have suggested various remedies for preventing thistearing. For instance it has been suggested that the internal walls ofthe ingot mold should be lubricated and/ or should be caused toreciprocate vertically. However all these suggestions appear to havesubstantial disadvantages. Moreover the use of copper molds forcontinuous casting has the disadvantage that small molten particles orcopper are plucked off from the internal walls of the mold and diffuseinto the steel. In consequence the steel becomes red short as istestified by the appearance of flaws. In order to overcome thisdisadvantage it has been suggested that the inside of the mold should bechromium plated since chromium does not dissolve in steel at least notwhen it is used for lining continuous casting molds. It has also beenproposed to line ingot molds made of copper with other metals such asmolybdenum.

One particular object of the present invention is to provide a remedyfor the disadvantages enumerated above.

The present invention is essentially characterised in that the faces ofthe ingot mold making contact with the ingot are constituted, partiallyor totally, of cobalt or a cobalt alloy.

In accordance with the invention, the walls of the ingot mold can becovered with a protective coating of cobalt applied by spraying, forexample by means of a metal coating gun by means of a so-called plasmatorch, one or several layers being applied.

Alternatively, in accordance with the invention, the protective skin ofcobalt can be applied to the walls of the ingot electrolytically.

As an example of the cobalt alloy which can be employed in my invention,it is possible to use an alloy sold under the name of UMCo 50 containingamongst other elements, 50% of cobalt and approximately 30% of chromium.

This alloy can of course be applied by metal spraying ofelectrolytically.

Alternatively, instead of applying the alloy to the inner walls of theingot mold, the walls themselves can be made of the alloy, UMCo 50.

Furthermore the walls of the ingot mold can be made of cobalt.

One embodiment of the invention shown in the attached drawing which is avertical section.

In this drawing 1 denotes the casing of the mold which is generallycylindrical and is separated from the inner part of the mold by a gap 2serving for-the circulation of water which is supplied through annularducts 3 and 4 respectively at the bottom and top of the ingot mold.

Inside the casing 2 there is a copper sheath 5 of annular cross sectionand this is coated internally, by a process known as explosive platingwith UMCo 50. This coating is denoted by reference numeral 6 andreference numeral 7 is used to indicate the passage through which thesolidifying ingot passes downwards through the mold.

The composition of UMCo 50 is as follows:

C 0.05-0.12 Mn 0.5-1 Si 0.5-1 P max 0.02 S max 0.02 Cr 27-29 Co 48-52 FeRemainder Its physical properties are as follows:

Melting zone C 1380-1395 Specific gravit 8.05 Coeflicient of thermalexpansion C 16.8. l0 Thermal conductivity (25 C.) 0.0215

While I have described several forms of my invention in order that thoseskilled in the art may put it into effect, it is to be understood thatthe invention is not limited to the particular forms described above butis to be delimited by the gist and scope of the following patent claims.

I claim:

1. An ingot mold for the continuous casting of metals, the ingot moldhaving metal-contacting faces formed of cobalt.

2. An ingot mold for the continuous casting of metals, the ingot moldhaving internal faces covered with a protective layer of cobalt.

3. An ingot mold for the continuous casting of metals, the ingot moldhaving metal-contacting faces formed of an alloy of cobalt containing50% of cobalt and approximataely 30% of chromium.

4. An ingot mold for the continuous casting of steel having internalwalls formed by a cobalt containing alloy.

5. An ingot mold for the continuous casting of steel having internalwalls formed by a cobalt containing alloy containing 50% of cobalt andapproximately 30% chromium.

6. An ingot mold for the continuous casting of steel having internalwalls formed of an alloy consisting essentially of .05 to 12% carbon,27% to 29% chromium, 48% to 52% cobalt and the balance essentially iron.

References Cited UNITED STATES PATENTS 2,358,171 9/ 1949 Lindemuth 249114 3,035,934 5/1962 Cape 117-131 X 3,055,089 9/1962 Drummond 117-131 X3,059,325 10/1962 Taylor et al 117l31 X 3,102,044 8/1963 Joseph 11713l X3,302,251 2/1967 Speith et al. 249-116 X LAVERNE D. GEIGER, PrimaryExaminer. C. L. HOUCK, Assistant Examiner.

1. AN INGOT MOLD FOR THE CONTINUOUS CASTING OF METALS, THE INGOT MOLDHAVING METAL-CONTACTING FACES FORMED OF COBALT.